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Siddharth Suri “Cooperation in Static and Dynamic Networks”

Abstract: This talk describes the results of a series of web-based, behavioral
experiments designed to understand people's ability to cooperate in static
and dynamic networks. In the context of static networks, it was previously
thought that cooperation should fare better in highly clustered networks
such as cliques than in networks with low clustering such as random
networks. To test this hypothesis, we conducted a series of experiments, in
which 24 individuals played a local public goods game arranged on one of
five network topologies that varied between disconnected cliques and a
random regular graph. In contrast with previous theoretical work, we found
that network topology had no significant effect on average contributions. Since humans have a natural tendency to choose with whom to form new
relationships and with whom to end established relationships, we also study
cooperation in dynamic networks. Helping cooperators to mix assortatively
is believed to reinforce the rewards accruing to mutual cooperation while
simultaneously excluding defectors. Here we report on another series of
human subjects experiments in which groups of 24 participants played a
multi-player prisoner’s dilemma game where, critically, they were also
allowed to propose and delete links to players of their own choosing at
some variable rate. Over a wide variety of parameter settings and initial
conditions, we found that endogenous partner selection significantly
increased the level of cooperation, the average payoffs to players, and the
assortativity between cooperators. Joint work with Jing Wang (NYU) and Duncan Watts (Yahoo! Research).

Bio: Siddharth joined the Human & Social Dynamics group at Yahoo! Research led by Duncan Watts in August 2008. Prior to that he was a postdoctoral associate working with Jon Kleinberg in the computer science department at Cornell University. He earned his Ph.D. in computer and information science from the University of Pennsylvania in January 2007 under the supervision of Michael Kearns.